Improved burglar-alarm



STONE & LIVINGSTON.

Burglar Alarm.

No. 38,136. Patented April 7, 1863.

UNITED STATES PATENT OFFICE.

CHARLES H. STONE AND CHARLES W. LIVINGSTON, OF SOUTH GROTON,

' MASSACHUSETTS.

IMPROVED BURGLAR-ALARM.

Specification forming part of Letters Patent No. 38,136, dated April 7, 1863.

To all whom it may concern:

Be it known that we, CHARLES H. STONE and CHARLES W. LIVINGSTON, of South Groton, in the county of Middlesex and State of Massachusetts, have invented a new and Improved Burglar-Alarm; and we do hereby de- Glare that the following is a full and exact description thereof, reference being had to the accompanying drawings, and to the letters of reference marked thereon.

Figure l is a side elevation of the machine complete. Fig. 2 is a longitudinal section through the center, showing the internal arrangement of the ratchetgears and striking apparatus. Fig. 3 is a longitudinal section through the center, showing the spring and the lever that starts the alarm. Fig. 4 is a transverse section cut through the stop h, and shows the start J attached to the door and the lever i. It also shows the position of the ratchet wheel 0 and the crank-shaft b in the rear.

The same letters indicate like parts in all the figures.

The nature of our invention consists in constructing the alarm in such a manner that a door may be shut but cannot be opened without starting the alarm; also, of making such a combination of ratchet-gears, springs, &c., that a practical and effectual alarm may be constructed at a small expense.

' To enable others skilled in the art to make and use our invention, we will proceed to describe its construction and operation.

We construct our alarm with a spring and two ratchet gears and pawls, with lever-crank and bell. The gears, pawls, spring, and lever are confined in ametal box. The spring a in Fig. 3 is firmly attached to the crankshaft b, the ratchet-wheel 0, and its pawl k. (Shown in Fig. 2.) The ratchetwheel d and the double pawl e are so arrangedas to operate the hammerf, as shown in Figs. 2 and 4. The cranky and the stop h are so arranged as to hold the spring a stationary. (Shown in Figs. 1 and 3.) The lever t'projects below the metal box to reach the start J, which operates the stop It. (Shown in Figs. 1 and 4.)

Operation: The alarm may be fixed to any covenient place on the door-frame, and the start J fixed to the door in such a position as to operate the lever 13. The spring a is wound up by the crank g, and the stop h holds the power of the spring. The ratchet-wheel c is held by the pawl 70 that propels the ratchet d, and the ratchet-wheel d rocks the double pawl e, which operates the hammer f against the side of the bell. It will be seen that if the spring a is wound up, and the crank g resting on the stop h, that by shutting the door the start J simply crowds the lever 1' back, which forces the stop h a little farther forward, but on opening the door the start J moves the lever t'forward and operates to throw back the stop h, and the whole force of the spring it comes on the ratchet c and the pawl k, which causes the ratchet-wheel d to move and the double pawl e to rock, which throws the hammer f with force and great rapidity against the side of the bell.

What we claim as our invention, and desire to secure by Letters Patent, is-

The combination of the spring a and wheel 0, the pawl k, the wheel d, and the double pawl c with the hammer f; also, the combination of the lever t with the stop h, and crank g with the start J, constructed and operating substantially as described, and for the purposes set fort-h.

' CHARLES H. STONE.

CHARLES W. LIVINGSTON. Witnesses:

GEORGE E. BURT, CHARLES STUART. 

